[[alternative]]Studies of Dual-Band and Broadband Shorted Planar Patch Antennas for Wireless Communication Applications

碩士電機工程學系[[abstract]]本論文將以單饋入短路三角形平面天線結構設計出適用於無線通訊系統之雙頻帶及寬頻帶天線。其研究內容可分為三部份。首先，提出短路三角形平面天線之雙頻操作設計，即是在一個埋入V型槽孔的截頂三角形平面天線的邊緣處放置兩個短路牆，以激發兩個不同的共振模態，這兩個共振模態分別可輻射出類似單偶極天線及垂向特性之輻射場型。其次，利用耦合兩個具有相似輻射特性的共振模態來達到寬頻操作設計，這個設計其所需天線高度將小於0.06λ0且阻抗頻寬可超過25 %，一個天線樣品其頻寬可以涵蓋UMTS及ISM頻帶(1920 ~ 2483 MHz)也被實際製作完成。最後，提出雙頻及寬頻短路三角形平面天線之縮小化設計，所採用的方法是將短路三角形平面天線之輻射金屬面對稱的減半，並發現天線的操作頻帶及阻抗頻寬不會有太明顯的改變，因此天線輻射金屬面的面積將可減少50 %。此外，所有天線設計也將藉由電磁模擬軟體作數值分析，並將與實驗所得結果作一比較。[[abstract]]This thesis presents the designs of a single-feed shorted triangular patch antenna with dual-band and broadband operations. The thesis is mainly divided into three topics. First, the design of a shorted triangular patch antenna with dual-band operation is presented. By placing two shorting walls at the opposite edges of a tip-truncated triangular patch antenna with a V-shaped slot, two different resonant modes can be excited simultaneously. The two resonant modes can radiate a conical monopole-like pattern and a broadside pattern, respectively. Second, the method of coupling two resonant modes with similar radiation patterns is used to achieve the broadband antenna design. For the proposed design, the required antenna height is less than 0.06 free-space wavelengths, and the 10 dB impedance bandwidth is more than 25 %. In addition, a prototype with the operating bandwidth capable of covering UMTS and ISM bands (1920 ~ 2483 MHz) is implemented. Finally, the compact design of a shorted triangular patch antenna with dual-band and broadband operations is presented. For the shorted triangular patch antenna, when the antenna area is reduced by symmetrically halving the patch size, the operation frequency and the impedance bandwidth have not obvious variations. Consequently the patch size can be roughly reduced to 50 %. The simulations for the studied antennas in the thesis are also performed by using electromagnetic softwares, and they will be compared with the experimental results